vii DOMINANCE 77 



the ewes were hornless. In the F 2 generation raised from 

 these Fi animals both horned and hornless types ap- 

 peared in both sexes but in very different proportions. 



Fig. 15. 

 Fowls' feet. On the right a normal and on the left one with an extra toe. 



While the horned rams were about three times as nu- 

 merous as the hornless, this relation was reversed among 

 the females, in which the horned formed only about one- 

 quarter of the total. The simplest explanation of this 

 interesting case is to suppose that the dominance of the 

 horned character depends upon the sex of the animal — 

 that it is dominant in the male but recessive in the 

 female. A pretty experiment was devised for putting 

 this view to the test. If it is true, equal numbers of 

 gametes with and without the horned factor must be 

 produced by the F 1 ewes, while the factor should be lack- 

 ing in all the gametes of the hornless F 2 rams. A horn- 



